Benzoxazinoids from Scoparia dulcis (sweet broomweed) with antiproliferative activity against the DU-145 human prostate cancer cell line.

Sweet broomweed (Scoparia dulcis) is an edible perennial medicinal herb widely distributed in tropical and subtropical regions of Asia, Africa, and the Americas. Four compounds, (2R)-7-methoxy-2H-1,4-benzoxazin-3(4H)-one 2-O-β-galactopyranoside [(2R)-HMBOA-2-O-Gal], 3,6-dimethoxy-benzoxazolin-2(3H)-one (3,6-M2BOA), 3-hydroxy-6-methoxy-2-benzoxazolinone (3-OH-MBOA), and scutellarein 7-O-β-glucuronamide, along with eight known compounds, including two 7-methoxy-1,4-benzoxazin-3(2H)-one 3-O-hexopyranosides [(2R)-HMBOA-2-O-Glc and (2R)-HDMBOA-2-O-Glc], 6-methoxy-benzoxazolin-2(3H)-one (MBOA), acteoside, sodium scutellarin, p-coumaric acid, and two monosaccharides (fructose and glucose), were isolated from the aqueous extract of S. dulcis. Antiproliferative activities of the six benzoxazinoid compounds against the DU-145 human prostate cancer cell line were assayed, and one of these displayed an IC₅₀ of 65.8 μg/mL.